Curt did the measuring not I so you can email him from his webpage if you want more info. Thinking it through, what purpose would there be to excessively smooth FR when you're evaluating it for a project? It wouldn't make much sense would it?
Curt's been designing speakers for several decades and he simply doesn't make many if any mistakes.
HTH
Jim
Aurum Cantus AST2560 frequency curve
Jim,
I don't question the quality of the AC driver; it certainly is a good one.
Your frequency curve looks very nice, very flat; however the vertical scale is 5 dB/division.
Here is the frequency curve of the AST2560 datasheet, published by Aurum Cantus.
Look at the difference in the vertical scale: 1 dB instead of 5 dB of your curve.
Now the curve looks quite a bit less flat, especially between 4k5 and 8k or so.
No one would characterize the tweeter being extremely flat; it represents quite good the performance of the majority of tweeters.
Jim,
I don't question the quality of the AC driver; it certainly is a good one.
Your frequency curve looks very nice, very flat; however the vertical scale is 5 dB/division.
Here is the frequency curve of the AST2560 datasheet, published by Aurum Cantus.
Look at the difference in the vertical scale: 1 dB instead of 5 dB of your curve.
Now the curve looks quite a bit less flat, especially between 4k5 and 8k or so.
No one would characterize the tweeter being extremely flat; it represents quite good the performance of the majority of tweeters.
Attachments
I think you may have misunderstood my response. I wasn't bragging about how flat it was. However Curt told me he did flatten the response with the crossover about 5 db to pull the top end up and compensate for the roll off. The crossover is quite simple. Check with Curt if you want more info. He develops ideas that I come up with and collaborates on driver selection, cabinet design etc. with me. But, he's the brains of the collaboration, not me.
Jim
What you talking about?? My diy ribbons measure flat from 500 Hertz to 20k. I biamp and use a simple 1st order passive line level crossover (500 Hz). And as my ribbon is a flat 4 ohm resistive load then there is no need for conjugate loading (zobel network). So the amp plugs directly into the ribbon with zero passive components which will always confer a performance advantage (just need to watch out for DC offset
)They are a bit longer than the average ribbon - 58 inches - but since you didn't qualify your answer in any way then I can quite fairly call your bluff. No dome tweeter will match the bandwidth of a good ribbon.
And as another advantage, there is no vertical beaming. No need to position the ribbon at seating height..
This forum is for DIY Audio, there is way to much emphasis on commercial speakers in this thread.
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What you talking about?? My diy ribbons measure flat from 500 Hertz to 20k. I biamp and use a simple 1st order passive line level crossover (500 Hz). And as my ribbon is a flat 4 ohm resistive load then there is no need for conjugate loading (zobel network). So the amp plugs directly into the ribbon with zero passive components which will always confer a performance advantage (just need to watch out for DC offset
They are a bit longer than the average ribbon - 58 inches - but since you didn't qualify your answer in any way then I can quite fairly call your bluff. No dome tweeter will match the bandwidth of a good ribbon.
And as another advantage, there is no vertical beaming. No need to position the ribbon at seating height..
This forum is for DIY Audio, there is way to much emphasis on commercial speakers in this thread.
I am glad you like your ribbons. I am just wondering why most high end speakers don't use ribbons. Sonus Faber, B&W, Avalon and a bunch of them ... don't use ribbons.
Most people have the misconception that tweeters only play treble, but in reality it provides an overlay of "high" frequency that pervades the entire musical range. That is why I think able to play low is more important because it allows the tweeter to be able to integrate to the woofer. When I replaced the tweeter cap xover to Mundorf Supreme I was surprised one of the biggest improvement was the bass! Fans of ribbons always comment how precise, clear, smooth ribbons sound, but there is one variable which is how well it can be integrated to the woofer, but I still think dome tweeters can integrate better to the woofer. Maybe there is something about the shape of the dome that matches well with the woofer. Most people don't realize that all tweeters sound nice and good by itself, only when playing together with the woofer that's when they reveal their flaws.
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Troels said in many occasions he don't like ribbons for whatever reasons they don't sound right.
Monitor Audio, Dali, Proac, Goldenear, Roksan, Adam audio, Burmester, Quad, Focus, Elac, Gryphon, Infinity, Piega use ribbon's or AMT's.
Don't know if you even read my post. You dismissed my ribbons which go to 500Hz, then state that going low "is more important".
If low is important to you, is this not good enough? Which dome tweeters will go lower than this?
I also have a pair of Boehland Gaebener RD75 which I am not using right now. I previously used them with the same 500Hz 6dB crossover but the manufacturer's recommended crossover is 150Hz, 12dB. Sure the top end is limited over 15kHz, but what dome will go as low as the RD75?
Remember, low is more important because it allows the tweeter to be able to integrate to the woofer. Would like to know which tweeters you recommend to beat this performance.
The ScanSpeak AirCirc can play midrange. Most 1in. ScanSpeak dome can play fairly low. I am not familiar with your ribbon tweeter, but it seems like it was optimized to go low but limited to 15kHz. No real tweeter can play 500hz unless it is compromised at high freq. I mean you could get a 2in. tweeter that can go even lower than 500hz but probably will be limited to 15KHz which mean you need another tweeter to take it from there.. I am not expecting my tweeter to play midrange but should be able to go low enough to be able to integrate to the woofer.
I don't know but I thought this thread is about home audio ... not car audio.
Note that the scale is 5dB per division. It is just barely maintaining within a 4dB window from 2K to 20K which isn't that impressive.
There are dome tweeters which are flatter, e.g.
https://www.parts-express.com/pedocs/specs/264-1016--tymphany-xt25tg30-04-spec-sheet.pdf
http://www.scan-speak.dk/datasheet/pdf/d2905-930000.pdf
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